Data commit

Task/Yellowstone-sequence/Kotlin/yellowstone-sequence.kotlin

@@ -0,0 +1,49 @@
+fun main() {
+    println("First 30 values in the yellowstone sequence:")
+    println(yellowstoneSequence(30))
+}
+
+private fun yellowstoneSequence(sequenceCount: Int): List<Int> {
+    val yellowstoneList = mutableListOf(1, 2, 3)
+    var num = 4
+    val notYellowstoneList = mutableListOf<Int>()
+    var yellowSize = 3
+    while (yellowSize < sequenceCount) {
+        var found = -1
+        for (index in notYellowstoneList.indices) {
+            val test = notYellowstoneList[index]
+            if (gcd(yellowstoneList[yellowSize - 2], test) > 1 && gcd(
+                    yellowstoneList[yellowSize - 1], test
+                ) == 1
+            ) {
+                found = index
+                break
+            }
+        }
+        if (found >= 0) {
+            yellowstoneList.add(notYellowstoneList.removeAt(found))
+            yellowSize++
+        } else {
+            while (true) {
+                if (gcd(yellowstoneList[yellowSize - 2], num) > 1 && gcd(
+                        yellowstoneList[yellowSize - 1], num
+                    ) == 1
+                ) {
+                    yellowstoneList.add(num)
+                    yellowSize++
+                    num++
+                    break
+                }
+                notYellowstoneList.add(num)
+                num++
+            }
+        }
+    }
+    return yellowstoneList
+}
+
+private fun gcd(a: Int, b: Int): Int {
+    return if (b == 0) {
+        a
+    } else gcd(b, a % b)
+}